| The original rig had the same sail area as the stayed rig. It was too powerful so the owner chopped 4m off each one.

In the asking stupid questions realm, how is a rig too powerful? Like can one not sail normally while reefed?

Why would you not want to have extra sail available?

Thank you for your patience.

| The dragging of the mooring down wind is hard to attribute to the wing masts as they would have reduced the windage vs the stayed rig.

Perhaps not less 'drag'? While a wing can have much less drag than a pole when feathered, a wing in a lift condition can have way more, if you count lift as 'drag', I think?

| If the boat had been sailing back and forth it is more likely that any dragging of the mooring would have been upwind, not down.

Nice catch.

| No idea where the centre of mass of the mast is, suspect it is just aft of the max thickness (~33% of the chord) which is where the sheer web runs and is also the axis of rotation.

Well then it has to be dynamically unstable. In my ameturish imagining of a carbon wing mast, I cannot see a Center of mass fore of the aerodynamic center without added weight in the nose.

| Wing masts are scary for cruisers. I had one on Elementarry during a cyclone (50 knots) and in the turbulent wind in the canal, it was rocking like a mad thing, probably would have capsized if it wasn't tied down. The wind at the top of the 7m mast was totally different from the bottom. No way could it weathercock. At sea in a gale, you could probably reverse the masts and run downwind with a drogue or sea anchor. In a marina or close to a weather shore in a big breeze, I doubt it would be much fun.

You have written about this before. I always wondered why you didn't drop the mast? Again, I know nothing, but it seemed worth asking.

And, it seems reasonable that a wing mast should be scary. Since the wing cannot be kept dynamically stable, because it flexes so much behind the axis of rotation, now you have an unstable flying (high thrust) surface at the top of a flexible mast getting fast clean air. That's a nightmare!

| Modern sails and wing masts are efficient. They are also expensive, short lived, require a lot of expensive hardware and a fair bit of skill.

Would you put the junk rig in this group? While on the topic, can you give you thoughts on a junk on a HP?

More noob questions follow...

| My aim is to build a wing rig which:)
| Is big enough for light air without extras
| Is easily reefed or removed if required
| Has twist control from zero to lots, to remove the need to reef in a lot of situations

How does twist help the need for reefing?

| Has no sail track or slides and does not need mast bearings.
| Adopts it's aerofoil shape automatically
| Has a high aspect ratio

By high, you mean like 6 to 1?

| Has no external frames, battens, etc
| Has no internal strings, pulleys, frames or joints.
| No vertical loads on the sail part so it can be built of cheap material

Like junk material? Or lighter?

| Solid leading edge
| Is light and cheap

Excellent!

| Thanks to you guys and the JRA for the motivation and ideas on how to do this.
|
| State of play:
| The mast (3 x 3m pieces joined), weighs about 16 kgs as i miscalculated the number of tows required for the first section. Should have been ~12 kgs all up. Not a big deal for the test bed. The first piece of wing was built from a flat panel with different weights of glass and foam locations so it would bend into the correct curve. It was close, but no cigar due to the difficulty of a smooth leading edge transition to the skins. The next one is being done on a masonite half mould using standard grade polystyrene with carbon stringers and egg crate (areas with the skins joined together to remove the core shear from the core) sections. First half panel (2.5m x 0.5m) weighs just under 1 kg.

Thanks for the details Rob!